December 2023 Mid/Long Term Pattern Discussion: Let it Snow!

[John1122]

Most of our long range looks are well into December now. Hopefully we can have a better winter than last year, which was an all-time worst here. The first week of the month looks to be near normal temp wise and probably drier than normal, even though CPC favors AN precip. 

[John1122]

The PNA/NAO/AO look potentially favorable in early December.  Eric Webber noted that December -NAO in strong Niño conditions often led to great patterns later in winter as well. 

 

[Matthew70]

I would not mind a normal temp & dry first weekend of December.  My daughter has a showcase soccer tournament in Memphis that weekend.  After that let it snow!

[John1122]

The GFS is insistent that the west coast will continue to replenish water supplies. 6-10+ inches of rain for the northern 2/3rds of California and there been various runs of up to 215 inches of snowfall over the next two weeks from Mammoth to Tahoe ski areas. 

Unfortunately for us, storms crashing into Northern California to Washington means we are going to remain warm like we did last winter while the west got buried. 

[Daniel Boone]

21 hours ago, John1122 said:

The GFS is insistent that the west coast will continue to replenish water supplies. 6-10+ inches of rain for the northern 2/3rds of California and there been various runs of up to 215 inches of snowfall over the next two weeks from Mammoth to Tahoe ski areas. 

Unfortunately for us, storms crashing into Northern California to Washington means we are going to remain warm like we did last winter while the west got buried. 

Unless we can get strong blocking ala., '95-96. Although that was pac jet and polar jet driven, Systems tracked generally ESE before turning ENE after reaching the upper SE.. although , that I rather rare. It's possible the STJ will deter any chance of the -NAO and the SER hookup also . 

[Carvers Gap]

Overnight ensembles continue to advertise a decent pattern by mid month.   Modeling has been bouncing around a lot, and I don’t trust them at this point.  A -NAO is beginning to present itself consistently across global ensembles to varying degrees.  Do we have a decent source region for the SE trough?  IDK, it doesn’t look like it now. But that could change.  Models originally had this pattern in the LR, lost it, and now it is back again.  Shoulder season model watching is not for the faint of heart.  

[Carvers Gap]

And I should add that NAOs are probably one of the most difficult features to predict.  With the -QBO, we can kind of guess that it will be there from a seasonal perspective.  but truly it gets squirrelly to nail down details.   Last year, it often hooked into the SER which is not all that common but also not unprecedented.  With the predisposition of the ENSO state for a SE trough, I think we avoid that for the most part this winter.  Source regions are going to be key.  Again, this has generally looked like a backloaded winter on seasonal modeling.  A switch to a favorable pattern during any part of December is considered bonus bucks.

[Itryatgolf70]

If we can get a -nao west based, the ensembles have been showing it and perhaps the op runs will soon. December would be a big time bonus to have even a remote chance at winter weather here imo

[Carvers Gap]

Here is an interesting tidbit from the Euro Weeklies today.  The snow mean for the foothills, NE TN Valley, and SW VA is 6-8" of snow for the 46d timeframe beginning today.  

[Carvers Gap]

Maybe it is just Friday night and the melatonin is making me feel good.....but I really like what I see in ensembles today. Lots of changes during the last 48 hours.....

[Holston_River_Rambler]

Looks like the OP 12z GFS might be headed for an epic phased gulf storm out in fantasy land. 

[Holston_River_Rambler]

15 minutes ago, Holston_River_Rambler said:

Looks like the OP 12z GFS might be headed for an epic phased gulf storm out in fantasy land. 

Well it was a near run thing at least. Just a little too much flattening in front of phasing shortwaves. 

[Carvers Gap]

The 12z NAM shows some light snow showers over the region after the front passes (north of I-40 and Plateau eastward, especially higher elevations).

[Daniel Boone]

34 minutes ago, Carvers Gap said:

The 12z NAM shows some light snow showers over the region after the front passes (north of I-40 and Plateau eastward, especially higher elevations).

Kind of suspected that to be the case. Mentioned that to locals here couple days ago.  Setup looks favorable for first Valley flakes as at the very least there should be enough residual moisture to produce at least small dendrites. 

[Carvers Gap]

Modeling has reverted to a bit of a "meh" look during the past couple of days.  Again, as we depart shoulder season LR modeling can still fool us pretty easily in the future (both for the good and bad).  This would definitely be a year I don't expect a fast start to winter.  So, no harm, no foul....

[Carvers Gap]

Cosgrove mentioned on social media today that he felt like changes were coming after mid-month due to the high configuration in Canada, but that it would take some time.  Honestly, to me things are on schedule if not a week or two ahead of schedule for Nino.  The only thing that surprised me is that fall was so warm.  Also, LC mentioned that the rain returning to the SE was a decent sign that the past regime is changing. 

Again, things look pretty benign in the short and medium range.  I am less bullish on a cold Christmas, but that could easily change.  I have seen LR modeling signal very cold Decembers only to have modeling flip after the first third of the month is over...and i have seen the opposite occur as well.  And again, this is the time of year when modeling struggles as the turn to winter is going to be not surprisingly late.

But man, it is cold out there today!!!!

[Daniel Boone]

Anybody see any flakes ? I didn't but, apparently some were falling above 2500 ft as could be seen on Mountains. 

     As far as the pattern, I wish I'd kept my hopes down regarding an early winter start. Many of us suspicioned that big warm pool off Japan was influencing/ altering the pattern causing a La nina background state within a strong Nino and affecting the MJO as well.

       It obviously is influencing the NA Pattern. Look at the intensity of that Firehose Pac Jet over that area ! Other Drivers are there but, that is a strong one. El Nino forcing will fight against it but, question is , will it pop the typical Aleutian Lp where we want it or be forced further east by that warm pool intensified Pac Jet... 

    

[Itryatgolf70]

10 minutes ago, Daniel Boone said:

Anybody see any flakes ? I didn't but, apparently some were falling above 2500 ft as could be seen on Mountains. 

     As far as the pattern, I wish I'd kept my hopes down regarding an early winter start. Many of us suspicioned that big warm pool off Japan was influencing/ altering the pattern causing a La nina background state within a strong Nino and affecting the MJO as well.

       It obviously is influencing the NA Pattern. Look at the intensity of that Firehose Pac Jet over that area ! Other Drivers are there but, that is a strong one. El Nino forcing will fight against it but, question is , will it pop the typical Aleutian Lp where we want it or be forced further east by that warm pool intensified Pac Jet... 

    

I don't expect a cold winter. Not many people do. I'm hoping we can get enough cold and precipitation to allow for a winter event at some point this winter. I always stay optimistic that it will somehow be colder but only time will tell.

[Carvers Gap]

And just like that, the 12z suite is a bit more interesting.   The GFS has a wave coming out of the GOM around 180.

[Carvers Gap]

22 minutes ago, Daniel Boone said:

Anybody see any flakes ? I didn't but, apparently some were falling above 2500 ft as could be seen on Mountains. 

     As far as the pattern, I wish I'd kept my hopes down regarding an early winter start. Many of us suspicioned that big warm pool off Japan was influencing/ altering the pattern causing a La nina background state within a strong Nino and affecting the MJO as well.

       It obviously is influencing the NA Pattern. Look at the intensity of that Firehose Pac Jet over that area ! Other Drivers are there but, that is a strong one. El Nino forcing will fight against it but, question is , will it pop the typical Aleutian Lp where we want it or be forced further east by that warm pool intensified Pac Jet... 

    

The ensembles aren't terrible at 500, but the source region is hot garbage.  That said the 12z operational runs are decent....what I can't tell is if the operationals are trying to catch-up to the ensembles, or in a rare case...it is the other way around.  LC had a great discussion on his Saturday night write-up and also a post earlier today.  He is reasonably optimistic.  He notes that changes(which were on the weeklies) can now be seen on operational and ensemble runs.  But he says it will take some time for the NA air mass to cool back down.  He did note that snowpack in Ontario and Quebec should build, and that would help place a semi-permanent trough over eastern NA by mid Jan.  He cautions patience, and notes that the Nino should begin to decay which would produce a weak Nino by mid-winter.  That would be huge.  Of course, there are always the stinker analogs from the 90s to keep us grounded!  Hope you had a great Thanksgiving.  

At least it looks like rains are returning at a fairly regular clip!  Jeff's post earlier is prob on the money about the first half of Dec being warm....though I was not a huge fan of the '22 cold coming all at once reference.  I hope that wasn't a hint.  That was prob too much cold in my book - at least the wind chills anyway!!!

If the winter is AN (temps) in eastern areas, the first two weeks of Dec will likely decide that.  If it is just +3-5F, I think the rest of DJF will off set that with Feb being the tipping point for BN.  As a whole, it would not surprise me to see the winter be slightly AN temp wise, but with seasonal snow for eastern areas.  Again, the opposite of last winter is very much in play.  But....no slam dunk!

[Daniel Boone]

23 minutes ago, Carvers Gap said:

The ensembles aren't terrible at 500, but the source region is hot garbage.  That said the 12z operational runs are decent....what I can't tell is if the operationals are trying to catch-up to the ensembles, or in a rare case...it is the other way around.  LC had a great discussion on his Saturday night write-up and also a post earlier today.  He is reasonably optimistic.  He notes that changes(which were on the weeklies) can now be seen on operational and ensemble runs.  But he says it will take some time for the NA air mass to cool back down.  He did note that snowpack in Ontario and Quebec should build, and that would help place a semi-permanent trough over eastern NA by mid Jan.  He cautions patience, and notes that the Nino should begin to decay which would produce a weak Nino by mid-winter.  That would be huge.  Of course, there are always the stinker analogs from the 90s to keep us grounded!  Hope you had a great Thanksgiving.  

At least it looks like rains are returning at a fairly regular clip!  Jeff's post earlier is prob on the money about the first half of Dec being warm....though I was not a huge fan of the '22 cold coming all at once reference.  I hope that wasn't a hint.  That was prob too much cold in my book - at least the wind chills anyway!!!

If the winter is AN (temps) in eastern areas, the first two weeks of Dec will likely decide that.  If it is just +3-5F, I think the rest of DJF will off set that with Feb being the tipping point for BN.  As a whole, it would not surprise me to see the winter be slightly AN temp wise, but with seasonal snow for eastern areas.  Again, the opposite of last winter is very much in play.  But....no slam dunk!

Good post buddy. Yeah, LC still is optimistic. As with many he is a bit more reserved. I still haven't spoke with him. I'll give him a buzz and maybe get a little more out of him. I think with the continued intensification of El nino at this juncture has gun shyed some of us . The Japanese warm pool is more concern to me.

 As I mentioned on another forum, the strong Ninos of 82-83 and 97-98 were decent around here snowfall wise. It's the one's Don S. brought up that were terrible here. '72-73, 91-92, '94-95. Stinkers as you said, lol

     Btw, Wife was up early and saw flurries as did many other's here. Small flakes. 

 

[Daniel Boone]

1 hour ago, Itryatgolf70 said:

I don't expect a cold winter. Not many people do. I'm hoping we can get enough cold and precipitation to allow for a winter event at some point this winter. I always stay optimistic that it will somehow be colder but only time will tell.

Yeah. Hopefully we can land a couple storms at the least. Odds still better than last with active STJ. 

[John1122]

1 hour ago, Daniel Boone said:

Anybody see any flakes ? I didn't but, apparently some were falling above 2500 ft as could be seen on Mountains. 

     As far as the pattern, I wish I'd kept my hopes down regarding an early winter start. Many of us suspicioned that big warm pool off Japan was influencing/ altering the pattern causing a La nina background state within a strong Nino and affecting the MJO as well.

       It obviously is influencing the NA Pattern. Look at the intensity of that Firehose Pac Jet over that area ! Other Drivers are there but, that is a strong one. El Nino forcing will fight against it but, question is , will it pop the typical Aleutian Lp where we want it or be forced further east by that warm pool intensified Pac Jet... 

    

It snow showered here late last night and there were a few flurries this morning. Cold this afternoon. Only 34 so far. 

[Daniel Boone]

1 minute ago, John1122 said:

It snow showered here late last night and there were a few flurries this morning. Cold this afternoon. Only 34 so far. 

I don't think KJKL or KMRX ever even mentioned the possibility. Really surprised at that... Particularly JKL. 

[Carvers Gap]

MRX mentioned snow above 3k' I "think."

The 12z Euro also is picking up on an active (mostly rainy) wx pattern during the next ten days.  That storm around 170-180hr probably is going to have to be watched for frozen possibilities either with wrap around or with the storm itself.  There may be some minor upslope potential following it.  Still way out there, so lots of possibilities...but generally a slp tracking to our SE w/ marginal surface temps.

[Carvers Gap]

The good thing about the 12z suite is that I think winter might be tipping its hand in regards to storm track.....

[John1122]

1 hour ago, Daniel Boone said:

I don't think KJKL or KMRX ever even mentioned the possibility. Really surprised at that... Particularly JKL. 

The NAM did a good job sniffling it out here. 

[Holston_River_Rambler]

A little clipper action on the 18z GFS for eastern areas. 

[Carvers Gap]

18 minutes ago, Holston_River_Rambler said:

A little clipper action on the 18z GFS for eastern areas. 

Yep.  That is a decent run...lots of pieces on the board still.

[Carvers Gap]

3x NW flow type stuff and 1x WAA event on the 18z GFS.  I think it really depends if that trough can back more to the west.  If it does, we are in business.  If it does not, nada.